Adapt VolumeRenderer to changed FrameBuffer API
Adapt VolumeRenderer to changed FrameBuffer API

MengjiaoH/ospray,Twinklebear/OSPRay,ospray/OSPRay,Twinklebear/OSPRay,MengjiaoH/ospray,wilsonCernWq/ospray,ospray/OSPRay,wilsonCernWq/ospray,Twinklebear/OSPRay,MengjiaoH/ospray,ospray/OSPRay,Twinklebear/OSPRay,ospray/OSPRay,MengjiaoH/ospray,wilsonCernWq/ospray,MengjiaoH/ospray